package etl.dispatch.util;

import java.util.Collection;
import java.util.Map;
import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.lang3.StringUtils;

/**
 * Assertion utility class that assists in validating arguments. Useful for identifying programmer errors early and
 * clearly at runtime. <p>For example, if the contract of a public method states it does not allow {@code null}
 * arguments, Assert can be used to validate that contract. Doing this clearly indicates a contract violation when it
 * occurs and protects the class's invariants. <p>Typically used to validate method arguments rather than configuration
 * properties, to check for cases that are usually programmer errors rather than configuration errors. In contrast to
 * config initialization code, there is usally no point in falling back to defaults in such methods. <p>This class is
 * similar to JUnit's assertion library. If an argument value is deemed invalid, an {@link IllegalArgumentException} is
 * thrown (typically). For example: <pre class="code"> Assert.notNull(clazz, "The class must not be null");
 * Assert.isTrue(i > 0, "The value must be greater than zero");</pre> Mainly for internal use within the framework;
 * consider Jakarta's Commons Lang >= 2.0 for a more comprehensive suite of assertion utilities.
 * 
 * @author Keith Donald
 * @author Juergen Hoeller
 * @author Colin Sampaleanu
 * @author Rob Harrop
 * @since 1.1.2
 */
public abstract class AssertUtil {

    /**
     * Assert a boolean expression, throwing {@code IllegalArgumentException} if the test result is {@code false}. <pre
     * class="code">Assert.isTrue(i &gt; 0, "The value must be greater than zero");</pre>
     * 
     * @param expression a boolean expression
     * @param message the exception message to use if the assertion fails
     * @throws IllegalArgumentException if expression is {@code false}
     */
    public static void isTrue(boolean expression, String message) {
        if ( !expression) {
            throw new IllegalArgumentException(message);
        }
    }

    /**
     * Assert a boolean expression, throwing {@code IllegalArgumentException} if the test result is {@code false}. <pre
     * class="code">Assert.isTrue(i &gt; 0);</pre>
     * 
     * @param expression a boolean expression
     * @throws IllegalArgumentException if expression is {@code false}
     */
    public static void isTrue(boolean expression) {
        isTrue(expression, "[Assertion failed] - this expression must be true");
    }

    /**
     * Assert that an object is {@code null} . <pre class="code">Assert.isNull(value, "The value must be null");</pre>
     * 
     * @param object the object to check
     * @param message the exception message to use if the assertion fails
     * @throws IllegalArgumentException if the object is not {@code null}
     */
    public static void isNull(Object object, String message) {
        if (object != null) {
            throw new IllegalArgumentException(message);
        }
    }

    /**
     * Assert that an object is {@code null} . <pre class="code">Assert.isNull(value);</pre>
     * 
     * @param object the object to check
     * @throws IllegalArgumentException if the object is not {@code null}
     */
    public static void isNull(Object object) {
        isNull(object, "[Assertion failed] - the object argument must be null");
    }

    /**
     * Assert that an object is not {@code null} . <pre class="code">Assert.notNull(clazz,
     * "The class must not be null");</pre>
     * 
     * @param object the object to check
     * @param message the exception message to use if the assertion fails
     * @throws IllegalArgumentException if the object is {@code null}
     */
    public static void notNull(Object object, String message) {
        if (object == null) {
            throw new IllegalArgumentException(message);
        }
    }

    /**
     * Assert that an object is not {@code null} . <pre class="code">Assert.notNull(clazz);</pre>
     * 
     * @param object the object to check
     * @throws IllegalArgumentException if the object is {@code null}
     */
    public static void notNull(Object object) {
        notNull(object, "[Assertion failed] - this argument is required; it must not be null");
    }

    /**
     * Assert that the given String is not empty; that is, it must not be {@code null} and not the empty String. <pre
     * class="code">Assert.hasLength(name, "Name must not be empty");</pre>
     * 
     * @param text the String to check
     * @param message the exception message to use if the assertion fails
     * @see StringUtils#hasLength
     */
    public static void hasLength(String text, String message) {

        if ( !StringUtils.isNotEmpty(text)) {
            throw new IllegalArgumentException(message);
        }
    }

    /**
     * Assert that the given String is not empty; that is, it must not be {@code null} and not the empty String. <pre
     * class="code">Assert.hasLength(name);</pre>
     * 
     * @param text the String to check
     * @see StringUtils#hasLength
     */
    public static void hasLength(String text) {
        hasLength(text, "[Assertion failed] - this String argument must have length; it must not be null or empty");
    }

    /**
     * Assert that the given String has valid text content; that is, it must not be {@code null} and must contain at
     * least one non-whitespace character. <pre class="code">Assert.hasText(name, "'name' must not be empty");</pre>
     * 
     * @param text the String to check
     * @param message the exception message to use if the assertion fails
     * @see StringUtils#hasText
     */
    public static void hasText(String text, String message) {
        if ( !StringUtils.isNotBlank(text)) {
            throw new IllegalArgumentException(message);
        }
    }

    /**
     * Assert that the given String has valid text content; that is, it must not be {@code null} and must contain at
     * least one non-whitespace character. <pre class="code">Assert.hasText(name, "'name' must not be empty");</pre>
     * 
     * @param text the String to check
     * @see StringUtils#hasText
     */
    public static void hasText(String text) {
        hasText(text, "[Assertion failed] - this String argument must have text; it must not be null, empty, or blank");
    }

    /**
     * Assert that the given text does not contain the given substring. <pre class="code">Assert.doesNotContain(name,
     * "rod", "Name must not contain 'rod'");</pre>
     * 
     * @param textToSearch the text to search
     * @param substring the substring to find within the text
     * @param message the exception message to use if the assertion fails
     */
    public static void doesNotContain(String textToSearch, String substring, String message) {
        if (StringUtils.isNotEmpty(textToSearch) && StringUtils.isNotEmpty(substring)
            && textToSearch.contains(substring)) {
            throw new IllegalArgumentException(message);
        }
    }

    /**
     * Assert that the given text does not contain the given substring. <pre class="code">Assert.doesNotContain(name,
     * "rod");</pre>
     * 
     * @param textToSearch the text to search
     * @param substring the substring to find within the text
     */
    public static void doesNotContain(String textToSearch, String substring) {
        doesNotContain(textToSearch, substring,
            "[Assertion failed] - this String argument must not contain the substring [" + substring + "]");
    }

    /**
     * Assert that an array has elements; that is, it must not be {@code null} and must have at least one element. <pre
     * class="code">Assert.notEmpty(array, "The array must have elements");</pre>
     * 
     * @param array the array to check
     * @param message the exception message to use if the assertion fails
     * @throws IllegalArgumentException if the object array is {@code null} or has no elements
     */
    public static void notEmpty(Object[] array, String message) {
        if (ObjectUtils.isEmpty(array)) {
            throw new IllegalArgumentException(message);
        }
    }

    /**
     * Assert that an array has elements; that is, it must not be {@code null} and must have at least one element. <pre
     * class="code">Assert.notEmpty(array);</pre>
     * 
     * @param array the array to check
     * @throws IllegalArgumentException if the object array is {@code null} or has no elements
     */
    public static void notEmpty(Object[] array) {
        notEmpty(array, "[Assertion failed] - this array must not be empty: it must contain at least 1 element");
    }

    /**
     * Assert that an array has no null elements. Note: Does not complain if the array is empty! <pre
     * class="code">Assert.noNullElements(array, "The array must have non-null elements");</pre>
     * 
     * @param array the array to check
     * @param message the exception message to use if the assertion fails
     * @throws IllegalArgumentException if the object array contains a {@code null} element
     */
    public static void noNullElements(Object[] array, String message) {
        if (array != null) {
            for (Object element : array) {
                if (element == null) {
                    throw new IllegalArgumentException(message);
                }
            }
        }
    }

    /**
     * Assert that an array has no null elements. Note: Does not complain if the array is empty! <pre
     * class="code">Assert.noNullElements(array);</pre>
     * 
     * @param array the array to check
     * @throws IllegalArgumentException if the object array contains a {@code null} element
     */
    public static void noNullElements(Object[] array) {
        noNullElements(array, "[Assertion failed] - this array must not contain any null elements");
    }

    /**
     * Assert that a collection has elements; that is, it must not be {@code null} and must have at least one element.
     * <pre class="code">Assert.notEmpty(collection, "Collection must have elements");</pre>
     * 
     * @param collection the collection to check
     * @param message the exception message to use if the assertion fails
     * @throws IllegalArgumentException if the collection is {@code null} or has no elements
     */
    public static void notEmpty(Collection<?> collection, String message) {
        if (CollectionUtils.isEmpty(collection)) {
            throw new IllegalArgumentException(message);
        }
    }

    /**
     * Assert that a collection has elements; that is, it must not be {@code null} and must have at least one element.
     * <pre class="code">Assert.notEmpty(collection, "Collection must have elements");</pre>
     * 
     * @param collection the collection to check
     * @throws IllegalArgumentException if the collection is {@code null} or has no elements
     */
    public static void notEmpty(Collection<?> collection) {
        notEmpty(collection,
            "[Assertion failed] - this collection must not be empty: it must contain at least 1 element");
    }

    /**
     * Assert that a Map has entries; that is, it must not be {@code null} and must have at least one entry. <pre
     * class="code">Assert.notEmpty(map, "Map must have entries");</pre>
     * 
     * @param map the map to check
     * @param message the exception message to use if the assertion fails
     * @throws IllegalArgumentException if the map is {@code null} or has no entries
     */
    public static void notEmpty(Map<?, ?> map, String message) {
        if (map == null || map.size() == 0) {
            throw new IllegalArgumentException(message);
        }
    }

    /**
     * Assert that a Map has entries; that is, it must not be {@code null} and must have at least one entry. <pre
     * class="code">Assert.notEmpty(map);</pre>
     * 
     * @param map the map to check
     * @throws IllegalArgumentException if the map is {@code null} or has no entries
     */
    public static void notEmpty(Map<?, ?> map) {
        notEmpty(map, "[Assertion failed] - this map must not be empty; it must contain at least one entry");
    }

    /**
     * Assert that the provided object is an instance of the provided class. <pre
     * class="code">Assert.instanceOf(Foo.class, foo);</pre>
     * 
     * @param clazz the required class
     * @param obj the object to check
     * @throws IllegalArgumentException if the object is not an instance of clazz
     * @see Class#isInstance
     */
    public static void isInstanceOf(Class<?> clazz, Object obj) {
        isInstanceOf(clazz, obj, "");
    }

    /**
     * Assert that the provided object is an instance of the provided class. <pre
     * class="code">Assert.instanceOf(Foo.class, foo);</pre>
     * 
     * @param type the type to check against
     * @param obj the object to check
     * @param message a message which will be prepended to the message produced by the function itself, and which may be
     *            used to provide context. It should normally end in a ": " or ". " so that the function generate
     *            message looks ok when prepended to it.
     * @throws IllegalArgumentException if the object is not an instance of clazz
     * @see Class#isInstance
     */
    public static void isInstanceOf(Class<?> type, Object obj, String message) {
        notNull(type, "Type to check against must not be null");
        if ( !type.isInstance(obj)) {
            throw new IllegalArgumentException( (StringUtils.isNotEmpty(message) ? message + " " : "")
                                               + "Object of class ["
                                               + (obj != null ? obj.getClass().getName() : "null")
                                               + "] must be an instance of " + type);
        }
    }

    /**
     * Assert that {@code superType.isAssignableFrom(subType)} is {@code true}. <pre
     * class="code">Assert.isAssignable(Number.class, myClass);</pre>
     * 
     * @param superType the super type to check
     * @param subType the sub type to check
     * @throws IllegalArgumentException if the classes are not assignable
     */
    public static void isAssignable(Class<?> superType, Class<?> subType) {
        isAssignable(superType, subType, "");
    }

    /**
     * Assert that {@code superType.isAssignableFrom(subType)} is {@code true}. <pre
     * class="code">Assert.isAssignable(Number.class, myClass);</pre>
     * 
     * @param superType the super type to check against
     * @param subType the sub type to check
     * @param message a message which will be prepended to the message produced by the function itself, and which may be
     *            used to provide context. It should normally end in a ": " or ". " so that the function generate
     *            message looks ok when prepended to it.
     * @throws IllegalArgumentException if the classes are not assignable
     */
    public static void isAssignable(Class<?> superType, Class<?> subType, String message) {
        notNull(superType, "Type to check against must not be null");
        if (subType == null || !superType.isAssignableFrom(subType)) {
            throw new IllegalArgumentException(message + subType + " is not assignable to " + superType);
        }
    }

    /**
     * Assert a boolean expression, throwing {@code IllegalStateException} if the test result is {@code false}. Call
     * isTrue if you wish to throw IllegalArgumentException on an assertion failure. <pre class="code">Assert.state(id
     * == null, "The id property must not already be initialized");</pre>
     * 
     * @param expression a boolean expression
     * @param message the exception message to use if the assertion fails
     * @throws IllegalStateException if expression is {@code false}
     */
    public static void state(boolean expression, String message) {
        if ( !expression) {
            throw new IllegalStateException(message);
        }
    }

    /**
     * Assert a boolean expression, throwing {@link IllegalStateException} if the test result is {@code false}. <p>Call
     * {@link #isTrue(boolean)} if you wish to throw {@link IllegalArgumentException} on an assertion failure. <pre
     * class="code">Assert.state(id == null);</pre>
     * 
     * @param expression a boolean expression
     * @throws IllegalStateException if the supplied expression is {@code false}
     */
    public static void state(boolean expression) {
        state(expression, "[Assertion failed] - this state invariant must be true");
    }

}
